Is it possible to copy a certain property of a certain material to other materials?
While you can copy many object values to all other selected objects, we can only select one material at a time, leaving us with two options -


Copy an individual value CtrlC (CMDC on osx) and Paste it into the other materials CtrlV (CMDV on osx). Both of these actions work while the cursor is over the value for number, text and colour. Items like checkboxes and popup menus don't copy.
Use python (either a small script or type straight into the python console) to change the value of all or a subset of materials - this question can help with ways to define a list of materials.


While 1 is ok for a small number of materials 2 becomes necessary for larger changes.